IGCSE Biology Semester 1 Review Packet
1. The actual size of a woodlouse is 0.4mm but Robert drew is 5mm long. What is the magnification?
2. The nucleus in a photograph of a cell measures 3 mm across. If the magnification in the photograph is × 500, what is the
actual size of the nucleus?
3. A biology student working in a museum mixed up a series of specimens. The specimens are named in this list:
Amphibian
bacteria
bird
protoctist
mammal
fish
reptile
virus flowering plant
fungus
fern
insect
a. Body covered with fur; mammary glands
b. Cells with cell wall but no chlorophyll; reproduce by spores
c. Body covered with dry scales
d. Body has 3 regions: head, thorax, and abdomen
e. Single cell, without definite nucleus
f.
Can only reproduce within another living cell; few genes inside protein coat
g. Has feathers and a beak; maintains constant body temperature
4. All living organisms display certain characteristics. Complete the following sentences about these characteristics:
a. Releasing energy in cells is called…
b. The removal of waste products of the chemical processes in the body is called…
c. The ability to respond to changes in the environment is called…
5. Complete the table comparing monocots and dicots
Monocots
Cotyledons
Vein structure in
leaves
Roots
Vascular bundles
(xylem and phloem)
Flower parts
Dicots
6. Many seeds were germinated on damp sand. Random samples of 10 seedling were taken every 2 days. The fresh mass
and the dry mass of each sample were measured and are shown in the graph below.
a. State why the fresh mass and dry mass of a seedling are different.
b. Fresh mass is not a reliable measure of plant growth. Suggest why dry mass is more reliable measure of plant
growth.
c. Explain why 10 seedlings, rather than 1, were used for each sample.
d. Describe what happens to the fresh mass of the seedlings in the first 2 days after the seeds were set to
germinate.
e. Suggest a reason for this change in mass.
f.
Describe what happens to the dry mass of the seedlings during the first 8 days.
g. Suggest a reason for this change in mass.
7. The cells of the epidermis of the rhubarb stem contain a red pigment. This pigment makes it easy to see the cytoplasm
in these cells, and to observe how the cytoplasm in these cells and cell membrane are affected by the external
environment. Strips of rhubarb epidermis were placed in three different sucrose solutions. The strips were left in the
solutions for 30 minutes, and the cells were observed under the high-power objective lens of a light microscope. The
observations are recorded in the table below.
a. Name the process responsible for these changes in the cell’s appearance.
b. What term is used to describe the cell membrane that allows this process to occur?
c. What has happened to cause the cell membrane and cytoplasm to push against the cell wall in solution B?
d. What can you say about solution C to explain the appearance of the cells?
e. Complete the diagram below and add labels to show the cell membrane, cytoplasm, and vacuole of a cell
placed in solution A.
8. Fill in the missing words:
Diffusion
Osmosis
Photosynthesis
Active Transport
partially permeable membrane
cytoplasm
respiration
carbon dioxide amino acids
pathway
energy
concentration gradient
epidermis
Cell wall
swell
oxygen
glycogen
along against
lower
shrink
Animal cells contain _____________________, a semi- fluid solution of salts and other molecules, and are
surrounded by a ______________________. When surrounded by distilled water, the animal cells
_____________________ because the cell has a _____________________ water potential than the surrounding water.
Plant cells do not have this problem because they are surrounded by a ____________________.
In the gut, soluble food substances such as ____________________ cross the gut lining into the capillaries by the
process of ________, which is the movement of molecules down a ____________________. When an equilibrium is
reached between the gut contents and the blood, glucose may continue to be moved using the process called
_______________ which consumes _________________ and can move molecules _________________ a
concentration gradient.
The leaves of green plants obtain the gas ______________________ which they require for the process of
photosynthesis, by the process of ________________. The also lose the gas oxygen produced during
_________________ by the same process.
9. Define the term enzyme.
10. Enzymes are used in biological washing powders.
a. Describe how the presence of these enzymes may increase the efficiency of the washing powder in removing
stains from clothes.
b. Explain why the temperature of the wash needs to be carefully controlled.
c. Suggest a suitable temperature for a was using biological washing powder. Explain your answer.
11. Catalase, an enzyme, is present in all living cells including those of potato and liver. It speeds up the breakdown of
hydrogen peroxide as shown by the equation:
hydrogen peroxide (H2O2) → oxygen + water.
The oxygen is given off as a gas which can be collected over
water, as shown on the right.
The two different tissues, potato and liver, were used for
this investigation. Samples, each of 1 gram, were prepared
from both tissues. Some the samples were left raw and
others were boiled. Some samples were left as 1 cube and
others were copped into small pieces as shown in the first table on the
right.
2 cm3 H2O2 was added to each sample. The volume of O2 produced in 5
minutes was collected in the measuring cylinders, as shown in the
table.
a. Complete the following table by reading the values for oxygen
collected in the measuring cylinders.
b. Plot the volumes of oxygen collected from the samples as a
bar chart.
c. Describe the differences in results between sample A for the potato and sample A for the liver.
d. There is a difference between the samples for A and B for liver. Suggest an explanation for this difference.
e. State the importance of samples C and D in this investigation.
12. The diagram shows the apparatus used to investigate the effect of light intensity on the rate of photosynthesis.
a. How would the light intensity be varied?
b. Suggest a suitable control for the investigation.
c. Name 2 factors that should be kept constant if this is to be a fair test.
d. The rate of photosynthesis was measured by counting the number of bubbles released into the test tube every
5 minutes. The results obtained are shown below.
i. Plot a graph of these results
ii. Use your graph to find the number of gas bubbles given off in a 5 minute period at a light intensity of
35 units.
iii. Describe and explain the relationship between light intensity and rate of photosynthesis.
iv. Suggest 1 way in which the results of the experiments could be made more reliable.
13. The graph shown below indicates the amount of sugar contained in the leaves of a group of plants, kept in a
greenhouse, over a 7 day period.
a. Write a word equation for the process that produces the sugar in plants.
b. Name the process shown by the equation.
c. Why does the sugar level rise and fall during the day?
d. Suggest a reason for the lower peak on day 3.
e. The greenhouse owner used an oil burner during the spring. Give 2 reasons why using the burner might
increase the yield of sugar produced.